Objective： To evaluate the clinical course of patients with small cell lung cancer （SCLC） as second primary malignancy. Methods： Among the 355 patients diagnosed with SCLC at Helen and Harry Gray Cancer Center of Hartford Hospital Connecticut USA between 1988 and 1998, the records of 48 patients, which had been diagnosed with other malignancies before their diagnosis of SCLC, were retro- spectively reviewed. Results： Forty-eight patients （13.5%） were diagnosed with other malignancies prior to their SCLC among which 43 had documented smoking history and 93% of them （40/43） were current/former smokers. Of the 28-second primary SCLC patients who were treated with standard method, 11 （39.3%） achieved CR. 12 （42.8%） achieved PR, and the RR was 82.1%. The median survival of the 28 treated with standard method was 11.3 months （5.1-77.7 months）, while that of the rest 19 untreated patients （1 of 20 was lost to follow-up） was only 2.0 months （0.5 34.0 months）. There was no significant difference in the median survival and RR between 165 treated first primary SCLC （13.5 months and 77.6% respectively） and 28 treated secondary primary SCLC （11.3 months and 82.1% respectively） （P〉0.05）. The patients who had prostate cancer were older and subjected to less treatments than those with skin cancer, so their survival was shorter than the latter （3.5 months vs. 15 months, P〈0.05）. Conclusion： The response and survival of the treated patients with SCLC as a second malignancy showed no difference as compared to the treated ones with SCLC only. Therefore, an active medical treatment is important to relieve symptom and prolong survival of the second primary SCLC patients.
